编辑代码

//JSRUN引擎2.0，支持多达30种语言在线运行，全仿真在线交互输入输出。 
// console.log("Hello world!            -  js.jsrun.net ");

function fn(map = [], ops = [], m, n) {
    let body = [];
    for (let i = 0; i < m; i++) {
        for (let j = 0; j < n; j++) {
            if (map[i][j] === 'H') {
                body = [{
                    x: j,
                    y: i,
                }];
                break;
            }
        }
    }
    const opsMap = {
        "U": {
            x: 0,
            y: -1,
        },
        "L": {
            x: -1,
            y: 0,
        },
        "D": {
            y: 1,
            x: 0,
        },
        "R": {
            x: 1,
            y: 0,
        }
    }
    let prevCmd = ops[0];
    for (let i = 0; i < ops.length; i++) {
        const cmd = ops[i];
        if (opsMap[cmd]) {
            prevCmd = cmd;
        } else {
            if (cmd === "G" && prevCmd) {
                const {x, y} = opsMap[prevCmd];
                const newHead = {
                    x: body[0].x + x,
                    y: body[0].y + y,
                }
                let newBody = [...body];
                if (!isValidHead(newHead)) {
                    return body.length
                }
                newBody.unshift(newHead);
                if (map[newHead.y][newHead.x] === 'F') {
                    map[newHead.y][newHead.x] = "E";
                } else {
                    newBody.pop();
                }
                if (isTouch(newHead, newBody)) {
                    return body.length;
                }
                body = newBody;
            }
        }
    }

    function isValidHead(newHead) {
        const {x, y} = newHead;
        if (x < 0 || y < 0 || x > n - 1 || y > m - 1) {
            return false;
        }
        return true;
    }

    function isTouch(newHead, newBody) {
        const {x, y} = newHead;
        for (let {x: cx, y: cy} of newBody.slice(1)) {
            if (x === cx && cy===y) {
                return true;
            }
        }
        return false
    }
    return body.length
}

console.log(fn(
    [
        ['F', 'F', 'F', 'F', 'F'],
        ['F', 'F', 'F', 'F', 'F'],
        ['F', 'F', 'F', 'F', 'H'],
        ['F', 'F', 'F', 'F', 'F'],
        ['F', 'F', 'F', 'F', 'F'],
    ],
    ['U', 'G', 'G', 'G'],
    5,
    5
))

console.log(fn(
    [
        ['F', 'F', 'F', 'F', 'F'],
        ['F', 'F', 'F', 'F', 'F'],
        ['F', 'F', 'F', 'F', 'H'],
        ['F', 'F', 'F', 'F', 'F'],
        ['F', 'F', 'F', 'F', 'F'],
    ],
    ['L', 'G', 'G', 'G', 'D', 'G', 'R', 'G', 'G', 'G', 'U', 'G'],
    5,
    5
))

console.log(fn(
    [
        ['F', 'F', 'F'],
        ['F', 'F', 'H'],
        ['E', 'F', 'E'],
    ],
    ['D', 'G', 'G'],
    3,
    3
))